Paralleling the human immunodeciency virus (HIV) epidemic, there is growing number of both men and women infected with Herpes simplex virus type-1 (HSV-1) and Herpes simplex virus type-2 (HSV-2). HSV-1 causes mostly sores in the facial area (Herpes facialis), while in rare cases can cause severe encephalitis and blindness. HSV-2 causes infections in the genital organs (Herpes genitalis). In recent years an increasing number of cases have been reported with HSV-1 infections in the genital areas, while HSV-2 has been also increasingly isolated from facial sores indicating that these viruses can efficiently infect both sites. Both viruses have the ability to become latent (no virus production) in sensory ganglia and to induce recurrent infections following reactivation from external stimuli including stress, ultraviolet irradiation, immunosuppression and others causes. More than forty-five million Americans are currently infected with life-long infections of HSV-2. Seroprevalence rates range from 60-80% in developing countries, while in the US, HSV-2 seropositivity is approximately 23% in women and 11% in men. Overall, epidemiological studies have shown that HSV infection increases the risk of HIV-1 infection. These studies strongly suggest the need for the development of topical microbiocides to combat both infections.
During the past several decades, acyclovir has been the drug of choice for the treatment of herpetic infections. However, an increasing number of viral strains that are resistant to acyclovir inhibition has been reported, especially for immunocompromised individuals and organ and bone transplant recipients. Other drugs that work in a similar fashion with acyclovir to inhibit virus replication include foscarnet (trisodium phosphonoformate), which has a broad antiviral spectrum and in vitro activity against all human viruses of the herpes virus family, including cytomegalovirus, HSV, and varicella zoster virus. However, foscarnet intravenous administration has been reported to cause increased nephrotoxicity and other adverse reactions.
Topical formulations currently available to treat herpes infections include 5% acyclovir ointment (Zovirax®) and penciclovir cream (Vectavir® or Denavir®). These formulations have been noted to have limited efficacy, particularly against symptomatic recurrent herpes. Specifically, treatment of recurrent herpes with topical acyclovir demonstrated no or only limited clinical benefit.
A number of natural and readily available non-toxic synthetic compounds have been reported to have antiviral activities against Herpes simplex infections.
Cimetadine, an inexpensive OTC drug with potential immune enhancing properties, has been reported to have antiviral activity against both herpes simplex and herpes zoster viruses.
Coconut oil is thought to lyse lipid coated viruses such as the HSV and HIV viruses that contain a viral envelope.
Antiviral properties have been also attributed to vitamin A, vitamin C and zinc in combination, thought to result from enhancement of the immune responses against Herpes viruses.
BHT, an inexpensive food preservative and antioxidant, inactivates the Herpes virus (and other lipid coated viruses) by solubilizing the lipid coating around the virus.
Lysine supplements and diets with a high lysine/arginine ratio are believed by many to inhibit herpes virus replication.
Garlic and propolis have been also reported to have antiviral activities.
In most instances, scientific information about the antiviral properties of these compounds is rather limited. However, a number of over-the-counter products have been launched and are currently available based on rather anecdotal information about the antiviral properties of these compounds.
U.S. Pat. No. 6,455,580 discloses oral and parenteral administration of oleuropein, an olive leaf extract, for treatment of viral diseases, including Herpes.
U.S. Pat. No. 6,632,798 discloses administration of oleuropein for inhibiting angiogenesis, and for treatment thereby of a wide variety of diseases. Among the diseases mentioned are diseases associated with corneal neovascularization, including Herpes simplex and Herpes zoster infections.